An aerodynamic loss has been identified with the compressor discharge casing of some industrial gas turbines. The loss is produced by reacceleration of compressor discharge flow in narrowed areas or “pinch points” just downstream of the compressor diffuser, and it causes increased fuel consumption and reduced cooling of some combustion parts. Generally, newer turbine designs with multi-passage radial discharge diffusers or with redesigned flow sleeves, liners, etc. are not feasible for existing gas turbines because of high development and installation costs.
There remains a need, therefore, for a relatively low-cost solution suitable for field modification.